This is a multicenter randomized controlled open labeled study testing efficacy and tolerance of early launching of night non invasive ventilation in patients with myotonic dystrophy type 1(DM1). The object of this project is to estimate the effects of the early introduction of non invasive ventilation on the arisen of complication (non expected hospitalization, tracheostomy even death) with regard to a simple respiratory follow-up in patients affected by myotonic dystrophy.